This lesion is completely detached from the bone cortex by X-ray, so I doubt it will be a BPOP or osteochondroma. In addition, it has a zonal distribution pattern with very active osteoblastic and osteoclastic activity. I would think it is more like a heterotopic ossification. By any means, it is benign.

 骨软骨瘤，这个部位又叫甲下骨疣。

奇异性骨旁骨软骨瘤样增生

骨软骨瘤

 好病例。X线片及切片都好。赞一个。

奇异性骨旁骨软骨瘤样增生。即Nora病。